<template>
  <div id="app">
    <el-card shadow="always">
      <el-form :inline="true" size="medium" :model="studentSearch" class="demo-form-inline">
        <!--条件查询-->
        <el-form-item >
          <el-input v-model="studentSearch.name" placeholder="学生姓名"></el-input>
        </el-form-item>

        <el-form-item >
          <el-select v-model="studentSearch.cid" placeholder="所在班级">
            <el-option label="所有班级" value="0"></el-option>
            <el-option :label="c.className" :value="c.cid" v-for="c in classesList" :key="c.cid"></el-option>
          </el-select>
        </el-form-item>
        <el-form-item>
          <el-button type="primary" icon="el-icon-search"  plain @click="search">查询</el-button>
        </el-form-item>
        <el-form-item>
          <el-button type="success" icon="el-icon-plus" plain @click="addStudent">添加学生</el-button>
        </el-form-item>
        <el-form-item>
          <el-button type="danger" icon="el-icon-remove" plain @click="handleDelete">批量删除</el-button>
        </el-form-item>
      </el-form>
      <el-table
          :data="studentList"
          style="width: 100%"
          @selection-change="handleSelectionChange" >
        <el-table-column
            type="selection">
        </el-table-column>
        <el-table-column
            label="学号"
            align="center"
            prop="id"
            width="180"/>
        <el-table-column
            label="姓名"
            prop="name"
            align="center"/>
        <el-table-column
            label="年龄"
            prop="age"
            align="center"/>
        <el-table-column
            label="所在班级"
            prop="className"
            align="center"/>
        <el-table-column label="操作" align="center">
          <template slot-scope="scope">
            <el-button
                size="mini"
                @click="handleEdit(scope.$index, scope.row)">编辑</el-button>
            <el-button
                size="mini"
                type="danger"
                @click="handleDelete(scope.$index, scope.row)">删除</el-button>
          </template>
        </el-table-column>
      </el-table>
      <!--分页导航面板-->
      <el-pagination
          @size-change="handleSizeChange"
          @current-change="handleCurrentChange"
          :current-page="page"
          :page-sizes="[5, 10, 15, 20]"
          :page-size="pageSize"
          layout="total, sizes, prev, pager, next, jumper"
          :total="total">
      </el-pagination>
    </el-card>
    <!--新增/编辑对话框-->
    <el-dialog :title="title" :visible.sync="dialogFormVisible" :close-on-click-modal="false">
      <el-form :model="student" :rules="rules" ref="ruleForm">
        <el-form-item label="学生姓名" prop="name" :label-width="formLabelWidth">
          <el-input v-model="student.name" autocomplete="off"></el-input>
        </el-form-item>
        <el-form-item label="学生年龄" prop="age" :label-width="formLabelWidth">
          <el-input v-model.number="student.age" autocomplete="off"></el-input>
        </el-form-item>
        <el-form-item label="所在班级" prop="cid" :label-width="formLabelWidth">
          <el-select v-model="student.cid" placeholder="请选择所在班级">
            <el-option label="所有班级" value="0"></el-option>
            <el-option :label="c.className" :value="c.cid" v-for="c in classesList" :key="c.cid"></el-option>
          </el-select>
        </el-form-item>
      </el-form>
      <div slot="footer" class="dialog-footer">
        <el-button @click="dialogFormVisible = false">取 消</el-button>
        <el-button type="primary" @click="saveStudent">保 存</el-button>
      </div>
    </el-dialog>
  </div>
</template>

<script>
import studentApi from "@/api/student"
import classesApi from "@/api/classes"
export default {
  data() {
    let checkAge = (rule, value, callback) => {
      if (value === '' || value == null) {
        return callback(new Error('年龄不能为空'))
      } else if (!Number.isInteger(value)) {
        return callback(new Error('年龄必须为数字值'))
      } else if (value < 1 || value > 200) {
        return callback(new Error('年龄必须在1-200之间'))
      } else {
        callback()
      }
    }
    return {
      studentList: [],
      page: 1,        // 当前页
      pageSize: 5,    // 每页显示记录条数
      total: 100,     // 总记录数
      studentSearch:{}, // 查询条件对象
      classesList:[],   // 所有班级
      ids:[], //选中的学生ID
      student: {},       // 代表添加或修改的学生对象
      title: '',  //对话框标题
      dialogFormVisible:false,
      formLabelWidth: '120px',  // 代表表单的标签宽度formLabelWidth: '120px',  // 代表表单的标签宽度
      rules: {
        // 校验学生姓名
        name: [
          {required: true, message: '请输入学生姓名', trigger: 'blur'},
        ],
        // 校验学生年龄
        age: [
          { validator : checkAge, trigger: 'blur'}
        ],
        //校验学生班级
        cid: [
          {required: true, message: '请选择学生班级', trigger: 'blur'},
        ]
      }
    }
  },
  created() {
    this.search()
    this.findAllClasses()
  },
  methods: {
    // 1. 查询所有学生
    async findStudents() {
      const {data:res} = await studentApi.findAllStudents()
      console.log(res)
      if (data.code === 200) {
        this.studentList = res.data.list
      }
    },
    // 2. 分页查询
    async findByPage() {
      const {data:res} = await studentApi.findByPage(this.page,this.pageSize)
      console.log(res)
      if (res.code === 200) {
        this.studentList = res.data.pr.rows
        this.total = res.data.pr.total
      }
    },
    // 3. 查询所有班级
    async findAllClasses() {
      const {data:res} = await classesApi.findAllClasses()
      if (res.code === 200) {
        this.classesList = res.data.list
      }
    },
    // 4. 条件查询带分页
    async search(){
      this.studentSearch.classId = this.studentSearch.cid;
      const {data:res} = await studentApi.search(this.page,this.pageSize,this.studentSearch)
      console.log(res)
      if (res.code === 200) {
        this.studentList = res.data.pr.rows
        this.total = res.data.pr.total
      }

    },
    // 当pageSize大小发生改变时触发
    handleSizeChange(val) {
      this.pageSize = val
      this.search()
      console.log(`每页 ${val} 条`);
    },
    // 当页码page发生改变时触发
    handleCurrentChange(val) {
      this.page = val;
      this.search()
      console.log(`当前页: ${val}`);
    },
    handleEdit(index, row) {
      this.title = "编辑学生信息"
      this.student = row
      this.dialogFormVisible = true
    },

    //删除学生
    handleDelete(index, row) {
      this.ids = []
      if(row){  // 代表删除单个学生
        this.ids.push(row.id)
      }else{  //undefined时表示批量删除的情况
        this.ids = this.multipleSelection.map(m => m.id)
      }
      this.$confirm(`是否真的要删除学号为${this.ids}的学生吗?`, '提示', {
        confirmButtonText: '确定',
        cancelButtonText: '取消',
        type: 'warning'
      }).then(() => {       // 点击了"确定"按钮后执行
        let _this = this//其实和this.search()是等效的，但是这样编写可以使代码更加清晰，特别是在.then()里面又嵌套接口的情况，并且有可以避免意想不到的错误。
        studentApi.deleteStudent(this.ids)
            .then(({data:res}) => {
              if (res.code === 200) {
                this.$message({
                  type: 'success',
                  message: res.message,
                  onClose: () => {
                    // 重新加载数据
                    _this.search()
                  }
                })
              } else {
                this.$message({
                  type: 'error',
                  message: res.message
                })
              }
            })
      }).catch(() => {     // 点击了"取消"按钮后执行
        this.$message({
          type: 'info',
          message: '已取消删除'
        });
      });
    },
    addStudent() {
      this.title = "添加学生信息"
      this.student = {}
      this.dialogFormVisible = true
    },
    handleSelectionChange(val) {
      this.multipleSelection = val;
      console.log("选中信息"+JSON.stringify(this.multipleSelection))
    },
    saveStudent() {
      this.$refs.ruleForm.validate(async valid => {
        let url = "/student/add"      // 默认地址是添加学生
        let method = "post"           // 添加是post请求
        if(this.student.id){
          url = "/student/update"    // 如果有值就改为修改学生
          method = "put"             // 修改是put请求
        }
        if (valid) {
          this.student.classId = this.student.cid;
          const {data:res} = await studentApi.save(url,method,this.student)
          if (res.code === 200) {
            this.$message({
              type: 'success',
              message: res.message,
              onClose: () => {
                this.dialogFormVisible = false
                this.search()
              }
            })
          }else{
            this.$message({
              type: 'error',
              message: res.message
            })
          }
        } else {
          console.log("验证失败！")
          return false
        }
      })
    },
  }
}
</script>

<style>

#app{
  display: flex;
  justify-content: center;
}
.el-card{
  width: 90%;
}
.el-pagination{
  margin-top: 20px;
  text-align: right;
}
</style>
